节省的ImageIO回原来的大小 [英] ImageIO saves back to original size

问题描述

我一直在寻找从互联网上一些解决方案，但我还没有找到一个答案，我的问题。

I've been searching for some solutions from the internet yet I still haven't found an answer to my problem.

我已经工作或者做一个程序，它会从我的电脑得到的图像文件，然后将使用 Java的图形添加一些文本/对象/等进行编辑。在此之后，的Java的ImageIO 将保存新修改的图像。

I've been working or doing a program that would get an image file from my PC then will be edited using Java Graphics to add some text/object/etc. After that, Java ImageIO will save the newly modified image.

到目前为止，我能够很好地做到这一点，但我有一个关于图像的大小问题。原始图像和修改后的图像没有具有相同的尺寸。

So far, I was able to do it nicely but I got a problem about the size of the image. The original image and the modified image didn't have the same size.

原来是 2×3 英寸的图像，而经过修改的据称具有2x3inches太可悲了 8x14 英寸。所以，它比原来的走大。

The original is a 2x3inches-image while the modified one which supposedly have 2x3inches too sadly got 8x14inches. So, it has gone BIGGER than the original one.

解决方案是什么/ code，它会给我的2x3inches图像的输出，这将仍然有一个'好品质？

What is the solution/code that would give me an output of 2x3inches-image which will still have a 'nice quality'?

更新：

所以，这里的code我用。

So, here's the code I used.

public Picture(String filename) {
    try {
        File file = new File("originalpic.jpg");
        image = ImageIO.read(file);
        width  = image.getWidth();
    }
    catch (IOException e) {
        throw new RuntimeException("Could not open file: " + filename);
    }
}

private void write(int id) {
    try {
        ImageIO.write(image, "jpg", new File("newpic.jpg"));
    } catch (IOException e) {
        e.printStackTrace();
    }
}

月2日更新：

我现在知道什么是新形象的问题。当我从Photoshop检查它，它有不同的图像分辨率比原来的。原来有一个300像素/英寸，而新的图像具有72像素/英寸的分辨率。

I now know what's the problem of the new image. As I check it from Photoshop, It has a different image resolution compared to the original one. The original has a 300 pixels/inch while the new image has a 72 pixels/inch resolution.

如何能够改变使用Java分辨率？

How will I be able to change the resolution using Java?

推荐答案

要设置图像分辨率（JFIF段），你也许可以使用 IIOMetatada 为JPEG 。

To set the image resolution (of the JFIF segment), you can probably use the IIOMetatada for JPEG.

线沿线的东西：

public class MetadataTest {
    public static void main(String[] args) throws IOException {
        BufferedImage image = new BufferedImage(100, 100, BufferedImage.TYPE_3BYTE_BGR);

        ImageWriter writer = ImageIO.getImageWritersByFormatName("jpeg").next();
        writer.setOutput(ImageIO.createImageOutputStream(new File("foo.jpg")));
        ImageWriteParam param = writer.getDefaultWriteParam();

        IIOMetadata metadata = writer.getDefaultImageMetadata(ImageTypeSpecifier.createFromRenderedImage(image), param);
        IIOMetadataNode root = (IIOMetadataNode) metadata.getAsTree(metadata.getNativeMetadataFormatName());
        IIOMetadataNode jfif = (IIOMetadataNode) root.getElementsByTagName("app0JFIF").item(0);

        jfif.setAttribute("resUnits", "1");
        jfif.setAttribute("Xdensity", "300");
        jfif.setAttribute("Ydensity", "300");

        metadata.mergeTree(metadata.getNativeMetadataFormatName(), root);

        writer.write(null, new IIOImage(image, null, metadata), param);
    }
}

注意：此code不应该完全使用，但加入迭代，错误处理，流闭等，杂波的例子太多

请参阅 JPEG图像元数据DTD ，获取有关的元数据格式的文档，你可以控制的选项。

See JPEG Image Metadata DTD for documentation on the metadata format, and what options you can control.

这篇关于节省的ImageIO回原来的大小的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！